Ethanol-blended petrol is a great fuel, so what's the fuss?

The Australian press for the past few months has printed many articles about low-percentage blends of ethanol and petrol. The public has been left with the feeling that something is "wrong" with these fuels, and that the parties promoting ethanol in fuel are trying to foist something on an unsuspecting public that is somehow bad for them.

This article seeks to lay out the truth about ethanol, and as well tell the rest of the story: that it is fuels without ethanol that should give us cause for concern, because of the levels of toxic chemicals that they contain or emit during incomplete combustion.

What is ethanol?

Ethanol is an organic chemical, similar in properties to the hundreds of other components of petroleum-derived gasoline. Yet, there is a big difference: ethanol burns cleaner itself, and also it burns more completely the petrol it is blended into. This is due to the phenomenon of enleanment, possible because the ethanol is already partially oxidised.

Ethanol can be made from fossil fuels such as natural gas liquids or coal, but the source that is most valuable is natural raw materials like sugar cane or grains. This is because the raw material will be remade in exactly the same way during the following crop cycle. This is a result of the action of photosynthesis upon the carbon dioxide released during fermentation at the distillery or combustion in the automobile.

Ethanol and your car.

Engine performance and total emissions are both improved by the addition of ethanol to gasoline. The clean burning nature of ethanol allows you to capture more of the work from the fossil portion of the gasoline, which compensates largely for the lower energy content of ethanol itself. In a 10 per cent blend (E10), all other things being held the same, you might get a zero to 2.7 per cent loss in mileage (kilometres per litre).

Another performance benefit from ethanol is its high octane addition to fuel. Of all the commercially viable octane enhancers possible, nothing delivers more punch than ethanol. The populace still feels the ill effects of the tons of poisonous lead that were spewed into urban environments because of the poor decision to accept lead over ethanol as the octane additive of choice.

Comments have been made in the Australian press that ethanol octane benefits due to an increase in Research number is accomplished at the expense of the Motor number so that the benefit cancels. This is simply untrue. Octane is a measure of the resistance in an engine to damaging knock, which is premature detonation of the fuel before the spark plug fires at the optimal point in the cycle of crankshaft rotation. Research Octane Number is measured under normal driving conditions under light load on a level road. Motor Octane Number is best described as pulling a heavy trailer up a hill; that is, the engine is under considerable load. Like all high octane components added to gasoline, the Research number climbs higher with ethanol addition than the Motor Number, but certainly both values increase.

Other benefits due to ethanol in your car are technical in nature, but may be summarized as follows:

1. Cleans engine over time, especially harmful combustion chamber deposits.
2. Improved front end volatility for better cold start and improved operation (driveability and distillation curve effects).
3. Dissolves any fuel line and fuel tank water, which are sources of corrosion, and eliminates them out the exhaust.
4. The higher octane of the ethanol blend allows the new cars with higher compression ratio to run without changing refinery operations.

Exhaust versus evaporative emissions.

Adding ethanol to regular unleaded at 10 per cent is an easy way to make unleaded premium, and it extends supplies by 10per cent. Without any modification of the base gasoline, however, the vapour pressure of the fuel will increase slightly, leading to more evaporative, or fugitive, emissions. These are primarily vapours that escape the carbon canister on the automobile, or are forced into the air as the level in a fuel tank rises. They do not include fuel spills, because normally the entire volume of a gasoline spill will evaporate in any case.

The question is whether this greater evaporative mass gives rise to greater pollution potential than the large benefit of exhaust emissions reduction. It is my opinion as a fuel scientist that the nature of the chemical make-up of this new vapour space is less harmful that the unblended, but lower pressure, base gasoline. Ethanol itself, for example, which is now part of the vapour, has a lower ozone-forming potential than olefins and aromatics.

Ethanol and health.

After years of ethanol use in once-polluted major cities in the USA and Brazil, the air is demonstrably cleaner and within federal guidelines for a healthy lifestyle. Not only are toxic species reduced, such as carbon monoxide and aromatics, but also the potential to produce ground level ozone is lower because the elements necessary for its production have been greatly lessened. In particular, high octane benzene, known to cause leukaemia, can be nearly eliminated because ethanol can provide the octane it once did.

The benefit to citizens of urban airsheds is enormous. Cleaner air means healthier people, especially those that suffer from respiratory diseases. Mortality rates will improve, health care visits will decrease in number and severity, health care costs and insurance rates will benefit, and productivity will improve as absenteeism and performance is improved.

Experience

Ethanol has been blended in the US in significant levels since the early 1980s, and today blends of no more than 10per cent are warranted for use in every internal combustion engine sold, whether two stroke or four, land or water use, big engine or small. These are the same types of cars and marine engines sold in Australia, and there is no reason that ethanol blends at 10per cent or less will not work just fine. Additionally, in the US, there is a growing fleet of Fuel Flexible Vehicles (FFV) that runs on straight gasoline, straight ethanol, or anything in between. The number of stations dispensing the preferred fuel, E85, is growing. There are government incentives to car manufacturers for producing FFV.

Here at home, E10 has been trialled by BP successfully in the Brisbane market since April of 2002, with no negative incidents recorded. Over this same period, Q Fleet vehicles have also successfully run on E10. There has been intermittent blending in Queensland historically since 1927. Brazil, which also has abundant sugar resources, began blending during World War I. Today, all gasoline in Brazil contains 22per cent ethanol, and some fuel is straight ethanol. All cars in Brazil are specially designed for these levels of addition.

There are other countries besides the US, Brazil, and Australia that are incorporating ethanol into their motor fuels pool. In one form or another Sweden, France, Spain, India, Canada, Mexico and Thailand are actively using bio-ethanol at some substantial level.

Ethanol energy balance compared to gasoline.

Ethanol yields more energy net to the planet than it takes to produce it. Gasoline, or any fuel derived from fossil sources such as petroleum, cannot possibly do so. You are always at a deficit because you must consume some of the energy contained in the fuel to transport and process it, and you never get anything back. The carbon oxides from combustion add to the atmospheric inventory of other Greenhouse Gases.

With ethanol, the carbon dioxide produced either during fermentation or combustion will be remade into exactly the same amount of plant matter from which it was made. This photosynthetic cycle is what is meant by the renewable nature of ethanol, which in fact is classified as a solar fuel. Doing a complete energy balance, to include inputs at all levels of processing and giving credits where due, still makes for a positive balance using modern methods of farming and ethanol manufacture. This is an important part of what is meant by ethanol being sustainable.

Since carbon dioxide (CO2) is also heavily implicated in the atmospheric build-up of gases that are suspected agents of global climate change, it follows that, if the energy balance of ethanol is improved over fossil fuels, then burning it as a partial replacement for fossil fuels will help to abate these Greenhouse Gases. Further, there are two other subtle ways that ethanol helps in this area: (1) because unburned fuel is reduced in the tailpipe, more of it is being burned to useful work, and therefore additional fossil fuel will be saved; and (2) because of its high octane contribution, ethanol substitutes for aromatics, which give higher yields of CO2.

Another aspect of sustainability involves concerns about stress on the lands and tidal waters if ethanol use increases farming. There is little danger of this, as Australia can divert a portion of the agricultural commodities now shipped in export at increasingly low prices into ethanol manufacture, moving their value up the chain and improving prices for the remaining exports. Not one extra plot of land need be farmed to provide food on Australian tables and to produce fuel ethanol for our domestic needs.

Energy security.

Ethanol is a ready-to-use fuel that can be blended directly into gasoline. Australian refineries convert about 40per cent of crude runs to usable petrol. Therefore, one litre of ethanol produced in Australia substitutes for more than two litres of imported crude oil. This is not only helpful to the balance of payments but also provides us security of fuel supplies with content that is not dependent on foreign and uncontrolled sources. As a corollary, increasing numbers of jobs, in the rural areas where they are needed, will be created with widespread E10 usage.

Limit of ethanol in petrol.

Strong evidence exists that ethanol blends up to 10per cent are, in the words of the US Environmental Protection Agency, "substantially similar to gasoline." Every manufacturer of petrol-burning engines, for any transport application in the US, warrants the use of E10 as acceptable, and some go so far as to recommend it.

While there is no compelling evidence that blends up to 20per cent might cause harm to the current and future fleet of Australian automobiles, neither is there any evidence that harm will not be done, other than good fortune in the experiences so far.

Until such time as credible evidence proves otherwise, and the production of ethanol in Australia is so great that we can afford to provide some blends higher in percentage than E10, it is the opinion of this author that prudence requires that a limit of 10per cent be applied.

What is needed?

In order to grow a viable fuel ethanol industry, the federal government needs to establish a clear policy in support of alternative biofuels, and especially ethanol for petrol. The following actions are suggested for ethanol: (1) set volume targets with a timetable, (2) long term excise relief (or domestic producers credit) is needed to give lenders faith that debt will be repaid, (3) provide a capital subsidy for new ethanol capacity to attract investment capital from potential owners, (4) devise a mechanism to ensure market access, and (5) legislate fuel standards that include renewable fuels such as ethanol. These actions will level the playing field for all stakeholders in the fuel markets and give Australia a good chance or bringing to life a new and valuable industry.